Li Cheung is pedalling madly on the exercise bike. She is putting off her dinner until she is really hungry because fish paste makes her sick. She hears a loud racket and runs out into the other corridor, joining the other women. The lights flicker and she collides with Melissa. When the power comes back on, the women see a large blue box in the dining area.
The Doctor and Jo exit the TARDIS and introduce themselves. Jo is horrified to hear that the women are convicts and that their prison is a pod underwater. There are about ten of them. The water is filtered, fish is processed for food and chemicals are converted into power. The women provide the remaining power by using the exercise bikes.
Jo is appalled at the barbaric conditions and tries to convince the Doctor to free the women. She likens their situation to when the Doctor was “imprisoned” on Earth by the Time Lords. He promises to help the women, though he won't let them go free.
The Doctor talks with Li. The women don't want to escape, as that would lengthen their sentences. Only Miss Clark, who is a nutcase, is trying to escape by losing enough weight to fit into the tiny supply pod that arrives twice a year. The Doctor tells Li he will get the women out of there, but he is not freeing them. He is attacked by Clark, who thinks he will ruin everything. A couple of the other women pull Clark away, and the Doctor hypnotises her, calming her.
The Doctor tinkers with the transmitter, allowing his sonic screwdriver to access it remotely to release the anchors holding the pod to the ocean floor. The women will need to provide extra power on the exercise bikes.
As two of them are pedalling, Clark comes and threatens to kick open the hatch. She grabs Jo by the neck. The Doctor is ready to hypnotise her again but she tightens her grip on Jo's neck.
Suddenly the room lurches and everyone stumbles. The Doctor strikes Clark on the back of her neck. The room continues to lurch, and when it stops, Jill and Vijay open the hatch. The women climb out to the top, into the sunlight. The Doctor and Jo follow, and they see thousands of similar prison pods floating on the surface. The Doctor tells Jo that was why he had the women generate extra power, in order to free all of the pods. He and Jo make a discreet departure.
- Jo convinces the Doctor to help the women by reminding him of his recent imprisonment by the Time Lords.
- The Doctor pretends that he and Jo are travelling psychiatrists.
- The Doctor uses his sonic screwdriver to modify the transmitter.
- The stories in Short Trips: Steel Skies are divided into four sections dealing with different types of confinement. This story deals with incarceration, that is, "punishment and imprisonment".
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